The present invention relates to a method for effecting solubilization of interferon in water and an interferon-containing composition which is easily soluble in water.
Interferon is a physiologically active substance expected to be useful as a therapeutic agent because of its biological activities such as antivirus, anti-cancer and like activities. Interferon is classified into type .alpha., type .beta., type .gamma., etc., according to the physiological and physicochemical properties, and the origin. Heretofore, interferon has been produced by incubating cells of animals, in particular, cells of humans. However, since the supply of such cells was limited, there has been developed a process for producing interferon which comprises cloning an interferon gene by recombinant DNA technology, introducing it into a microorganism; e.g., E. coli, and incubating the microorganism.
Interferon is only slightly soluble in water so that it is difficult to isolate and purify from the culture. Thus, a procedure for solubilizing interferon has been sought.
For the purification of interferon-.beta., a method using blue Sepharose column is known. In this method, interferon is solubilized using ethylene glycol in an eluate [Jankowski, W. J., et al, Biochemistry, 15, 5182 (1976), Knight, E., Jr., Science, 207, 525 (1980)], but adequate results from this method have not been obtained yet.
Furthermore, Japanese Published Unexamined Patent Application No. 102519/1980 discloses that aromatic amino acids such as tryptophan, phenylalanine, tyrosine, etc., are effective for stabilizing interferon.
However, aromatic amino acids are not readily soluble in water and, therefore, are undesirable as reagents for solubilizing interferon.